Vulnerability runbook - Wasmtime

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# Vulnerability Runbook

This document outlines how Wasmtime maintainers should respond to a security vulnerability found in Wasmtime. This is intended to be a Wasmtime-specific variant of the runbook RFC originally created. More details are available in the RFC in some specific steps.

Vulnerabilities and advisories are all primarily coordinated online through GitHub Advisories on the Wasmtime repository. Anyone can make an advisory on Wasmtime, and once created anyone can be added to an advisory. Once an advisory is created these steps are followed:

1. An Incident Manager is selected. By default this is the Wasmtime maintainer that opened the advisory. If a contributor opened the advisory then it's by default the first responder on the advisory. The incident manager can, at any time, explicitly hand off this role to another maintainer.

2. Fill out the advisory details. This step involves filling out all the fields on the GitHub Advisory page such as:

   - Description - the description field's initial placeholder has the various sections to fill out. At this point at least a brief description of the impact should be filled out. This will get fleshed out more later too.
   - Affected versions - determine which previously released versions of Wasmtime are affected by this issue.
   - Severity - use the CVSS calculator to determine the severity of this vulnerability.

3. Collaborate on a fix. This should be done in a private fork created for the security advisory. This is also when any collaborators who can help with the development of the fix should also be invited. At this time only the `main` branch needs to have a fix.

4. Finalize vulnerability details and patched versions. After a fix has been developed and the vulnerability is better understood at this point the description of the advisory should be fully filled out and be made ready to go to the public. This is also when the incident manager should determine the number of versions of Wasmtime to patch. All supported releases documented must be patched, but the incident manager may also elect to patch more releases if desired.

5. Request a CVE. Use the Big Green Button on the advisory to request a CVE number from GitHub staff.

6. Send advanced disclosure email. The incident manager will decide on a disclosure date, typically no more than a week away, and send mail to sec-announce@bytecodealliance.org about the upcoming security release. An example mail looks like this

7. Add more stakeholders (optional). Users interested in getting advanced notice about this vulnerability may respond to the mailing list post. The incident manager will add them to the security advisory.

8. Prepare PRs for patch releases. This will involve creating more pull requests in the private fork attached to the advisory. Each version of Wasmtime being patched should have a PR ready-to-go which cleanly applies. Be sure to write release notes on the PR for each release branch.

9. The full test suite should be run locally for `main`. Locally try to run as much of the CI matrix as you can. You probably won't be able to run all of it, and that's ok, but try to get the ones that may have common failures. This is required because CI doesn't run on private forks.

10. Open version bump PRs on the public repository. Use the online trigger for this workflow to open PRs for all versions that are going to be patched. DO NOT include patch notes or release notes for this fix. Use this time to fix CI by landing PRs to the release branches separate from the version bump PR. DO NOT merge the version bump PR.

11. Manually make PRs on release day. DO NOT merge via the security advisory. This has generally not worked well historically because there's too many CI failures and branch protections. On the day of the release make public PRs from all of the previously-created PRs on the private fork. You'll need to push the changes to your own personal repository for this, but that's ok since it's time to make things public anyway. Merge all PRs (including to `main`) once CI passes.

12. Merge version bump PRs. Once the fixes have all been merged and CI is green merge all the version bump PRs. That will trigger the automatic release process which will automatically publish to crates.io and publish the release.

13. Publish the GitHub Advisories. Delete the private forks and hit that Big Green Button to publish the advisory.

14. Send mail about the security release. Send another around of mail to sec-announce@bytecodealliance.org describing the security release. This mail looks like this.

15. Add the advisory to the RustSec database. We mirror our advisories into the RustSec database for projects using Cargo-based tooling to check for security issue with their dependencies. An example of this is RUSTSEC-2024-0440. File a PR with the RustSec/advisory-db repository adding a new file in the `crates/wasmtime` directory. You'll use the file name `RUSTSEC-0000-0000.md` and can copy metadata from a previous advisory. The description should just point to the GitHub advisory published prior.

You'll want to pay close attention to CI on release day. There's likely going to be CI failures with the fix for the vulnerability for some build configurations or platforms and such. It should be easy to fix though so mostly try to stay on top of it. Additionally be sure to carefully watch the publish process to crates.io. It's possible to hit rate limits in crate publication which necessitates a retry of the job later. You can also try publishing locally too from the release branch, but it's best to do it through CI.